This invention relates to methods and apparatus for monitoring environmental conditions in restricted spaces, and more particularly to methods and apparatus for monitoring elevator hoistways for fire or smoke, and which provide convenient access for maintenance purposes without the need to take the associated elevator out of service.
Larger buildings, typically commercial and public buildings having multiple floors or stories, also include one or more elevators for providing convenient access to each floor without having to climb stairs. These elevators traverse a vertical shaft or hoistway in the building, either on a hydraulic lift or on a cable. For the safety of building occupants, particularly because elevators and their associated machinery present a significant fire danger, fire codes require that these hoistways be monitored for environmental conditions such as fire and smoke, by the placement of one or more environmental sensing units, such as smoke detectors and/or heat sensors, within each hoistway. The hoistway is also to be enclosed by fire protection rated walls in the event of a fire therein, in order to give building occupants sufficient time to exit the building safely.
In order to ensure the continued operability of these environmental sensing devices or units, fire codes require that they be inspected and tested periodically. The inspection and testing procedure typically involves shutting down the associated elevator, so that maintenance and/or fire department personnel can enter the hoistway and physically inspect and test the device. Such a procedure is time consuming and inconvenient, both for the personnel performing the procedure and for the building occupants, who must tolerate the reduced elevator service available from the remaining elevators in the building, or take the stairs.
What is needed, therefore, is an environmental monitoring system for elevator hoistways which permits an appropriate number of environmental sensing units to be placed in each hoistway, in desired locations for acceptable coverage thereof, but which also permits servicing and testing personnel to access those units whenever desired, without the need to enter the hoistway and thereby necessitate shutting down the associated elevator.
The present invention solves the aforementioned problems by providing an environmental monitoring system which is particularly suited for elevator hoistways and other locations where access is difficult or restricted. The invention comprises a fire rated access cage which is disposed within the hoistway in a desired location, and is securely attached to an associated access panel. The access panel is fire protection rated and positioned to extend through a wall defining the hoistway. An environmental sensing device, preferably a smoke detector, but alternatively a heat sensor or other suitable device, is secured within the cage so that it is disposed within the hoistway, and can freely detect negative environmental conditions, such as heat or smoke, present in the hoistway because of a large number of apertures in the walls of the cage. The resultant system is thus constructed so that authorized personnel can access the environmental sensing unit conveniently through the access panel door from an adjacent hallway or room to test or maintain it, without shutting down the associated elevator or compromising the effectiveness of the unit.
More particularly, there is provided an apparatus for use in monitoring spaces affording restricted access, which comprises an access panel including a door and a cage attached to the access panel. The cage has a plurality of openings or apertures for ensuring fluid communication between an interior portion of the cage and a surrounding space. Preferably, these apertures are present because the cage comprises expanded metal. An environmental sensing unit, such as a smoke detector or heat sensor, is secured within the interior of the cage. As a result, when the cage is installed, the smoke detector resides within the space affording restricted access, preferably an elevator hoistway, within an interior portion of the cage. The cage is preferably welded to the access panel, which further includes a frame, with the cage being welded to the frame.
In another aspect of the invention, there is disclosed a method for monitoring environmental conditions in a space affording restricted access. The method comprises steps of placing an access enclosure through an opening in a wall adjacent to the space, wherein the access enclosure comprises an access panel including a door and a cage attached to the access panel. The cage has a plurality of openings for ensuring fluid communication between an interior portion of the cage and a surrounding space. Further steps include disposing an environmental sensing device within the interior portion of the cage and opening the door to inspect or test the device.
In still another aspect of the invention, there is disclosed a method for monitoring environmental conditions in a space affording restricted access, preferably an elevator hoistway, without entering the space. The method comprises the steps of opening a door in an access enclosure from a second space adjacent to the restricted access space, and inspecting or testing an environmental sensing device disposed in the access enclosure. The method preferably includes a further step of maintaining normal operations in the restricted space while the inspecting or testing step is performed.